1. Field of the Invention
The present invention relates to a digital transmitter/receiver system, and more particularly to an error correction coding/decoding device and method for a digital transmitter/receiver system.
2. Description of the Related Art
FIG. 1 is a schematic block diagram of an error correction coding device of a transmitter system of the United States ATSC standard. Referring to FIG. 1, the error correction coding device 100 includes a randomizer 111, an RS (Reed-Solomon) encoder 113, an interleaver 115, and a trellis encoder 117.
Here, it is exemplified that the RS encoder 113 comprises an RS (207,187), t=10 code, which has an error correction capability of 10 bytes. An RS data block has a size of 207 bytes including input data of 187 bytes and an RS parity of 20 bytes, which is added for the error correction, and constitutes one segment (hereinafter referred to as “packet”) along with a segment sync signal.
The input data, which is inputted from an MPEG transport system, has a structure of an MPEG2-TS (Transport Stream) in which one packet is composed of 188 bytes. The MPEG2-TS packet is composed of a 1-byte sync signal, 3-byte header including a PID (Packet Identifier), and 184-byte payload data.
The input data is converted into a random form in the randomizer 111, and the RS parity of 20 bytes for the error correction is added to the randomized data in the RS encoder 113. Then, the data is convolution-interleaved in the interleaver 115, and then trellis-encoded with a ratio of 2/3 through the trellis encoder 117.
Through the above-described process, the error correction encoding of the input data is performed.
FIG. 2 is a view illustrating the structure of a data frame for transmission. The randomization and the error correction coding are performed with respect to the input data, but are not performed with respect to the sync byte of the transport packet corresponding to the segment sync signal. That is, the data packet randomized and error-correction-coded is converted in a data frame for transmission, and a segment sync signal and a field sync signal are added to the data frame to be transmitted.
FIG. 3 is a schematic block diagram of a receiver system having an error correction decoding device corresponding to the error correction coding device of the transmitter system of FIG. 1. The error correction decoding device 300 includes a trellis decoder 311, a deinterleaver 313, an RS decoder 315 and a derandomizer 317 in the reverse order of the error correction coding device 100 of the transmitter system.
The error correction decoding device 300 of the receiver system as described above corrects an error occurring in the transmission channel environment and the transmitter system. Especially, the RS encoder 113 and the RS decoder 315 serve to correct a burst error in association with the convolution interleaver/deinterleaver.
Recently, as the necessity for indoor, portable and mobile receiving services of ground-wave digital broadcasts is increasing, it is required to stably receive data even in the inferior channel environments. However, the error correction coding method of the existing ATSC transmission system cannot guarantee a stable receiving of data in the inferior channel environment where many errors occur. Thus, there is a demand for a strong error correction coding device and method having a capability of correcting more errors.